I've turned down several night games in the past and more than likely will continue to do so in the future. Not saying they aren't fun. With the RIGHT PLAYERS night OPs are a freakin blast! Delta 9 attended a partial night OP at a well established field and the outcome was still no bueno. You had WAY too many new players with no common sense and self control. The were blasting 100rds non-stop at anything they heard regardless of engagement distances and before checking to see if they were friendlies. At one point, there was one kid that I could hear getting shot easily 1000k+ times by a group of around 10+ players. The kid was screaming 'HIT! HIT! HIT! AAAHHH! OH MY GOD, HHIIIITT!!!', but with everyone shooting so much no one could hear him. I wouldn't blame that kid for never wanting to ever set foot on a field again. On the other hand, when you have a well controler environment and a higher caliber of player, like at SoGo or the MACC, I'd go back to a night OP to either one of those places anytime.
The weather thing is total BS. Don't get me wrong, I've played in my fair share of crappy weather, and NEVER was I thinking to myself that it was making me better. I can also tell you and anyone else that is leary about playing in rain that 99.9% of the time you won't wave any issues with you gun due to the weather. I know some people like to act all macho like they have something to prove, but if it's weather like we had hear in Neosho yesterday, ~40* soaked from snow and and super cold breezy rain, I'd probably opt out too. Again though, get the right guys with the right clothing (thermals and rain gear) and it could be fun but not anymore so than when it's nice out.
The whole point I'm driving at for both topics is that YOU need to have fun. If you do any think you're gonna have fun, then by all means don't go! Sometimes just thinking you won't have fun can ruin your mood at a game and therefore spoil your own fun. Just try to get from airsoft or MilSim what YOU want to get from it.